Praising the "magnificent demonstration" by students and staff earlier this month, the letter's signatories claim that plans to raise tuition fees and scrap the education maintenance allowance will lead to the "destruction of broad-based, critical education".

Thousands of university students, schoolchildren and sixth-formers are expected to take part in a national walkout on Wednesday as protests against government plans for higher education – which saw more than 50,000 people march in London on 10 November – are stepped up across the country.

The earlier demonstration ended in violence when a small minority of protesters stormed Conservative party headquarters, breaking windows and scuffling with the police. But the letter says that the intention of the 290 signatories is to "fight alongside [students] in our institutions … to protect higher and further education for all". The government has announced plans to let universities charge fees of up to £9,000 a year. A vote in parliament could take place next month.

Funding for university teaching will also be cut, along with the education maintenance allowance, which pays 16- to 18-year-olds from low-income households up to £30 a week to continue their studies.

The signatories to today's letter – who are drawn from 68 UK universities and eight non-UK education institutions – say they consider themselves to be "involved in a defence, not just of our jobs, but of the values which brought us into higher education, reflecting the wider significance of education to society".

They go on to say that the planned increase in fees means the "effective removal of higher education" for working people.

The letter points to research from the Institute of Fiscal Studies which says that the cuts will lead to "insignificant savings to the taxpayer".

"The ending of the education maintenance allowance and adult learning grants gives the lie to the coalition's attempts to argue that those on lower incomes will retain access – these students will not be able to afford to stay in post-16 education to secure the qualifications they need to apply for further or higher education.

"The coalition has no mandate for its ideologically driven class rule – the anger of students is no surprise to us. Our intention is to fight alongside them in our institutions to defend social science, humanities and the arts and to protect higher and further education for all."

Among the signatories are Dr Hazel Conley, Queen Mary University of London; Professor Richard Hyman, London School of Economics; and Professor Stephen Bach, Kings College London.

Dr Peter Dwyer, Ruskin College Oxford; Alexander Anievas, University of Cambridge; Dr Vaughan Ellis, Edinburgh Napier University; and Dr Andrew Cumbers, University of Glasgow, have also put their name to the letter.

More than 20,000 school, college and university students have pledged to walk out of classes at 11am today in protest at plans to raise tuition fees and scrap the education maintenance allowance. Follow the latest developments here

More than 20,000 school, college and university students have pledged to walk out of classes at 11am today in protest at plans to raise tuition fees and scrap the education maintenance allowance. Follow the latest developments here